It is known to provide a wheel cover for a wheel of a vehicle. Typically, the wheel cover is generally circular in shape and made of a plastic or metal material. When the wheel cover is made of a plastic material, the plastic wheel covers have been observed to produce objectionable sound or noise such as "squeaks" under specific conditions of usage. These squeaks are usually detected in vehicles at low speeds, with the windows down, enabling an airborne path between the noise source and the occupants. The squeaks are characterized as bursts of sound concentrated in a band of frequencies extending from approximately 1 to 3 kHz. The bursts of sound, furthermore, occur as discrete events at repetitive subintervals of a rotation cycle of the wheel. Complaints typically characterize the condition as modulated sound or bursts of sound occurring once, twice or other multiples of the rotation cycle of the wheel.
Detailed diagnostics of the underlying excitation source of the disturbance have identified stick-slip conditions at the interface of relative sliding zones at contact sites between the wheel cover and the wheel. The wheel cover is typically attached to the wheel through plastic nuts engaging external threads on wheel lug nuts. Surfaces of the wheel cover also contact the wheel at other sites distant from the vicinity of the wheel lug nuts. These secondary zones of contact are intentional and required to achieve integrity of attachment and styling objectives.
The load of the vehicle is transmitted through the wheel. The wheel rotates through a deformation field (stationary with respect to a ground reference frame) developed due to this load support. As a point on the wheel rotates through this deformation field, relative movement occurs between the wheel and the wheel cover at some of the interfacial contact sites. Through a full rotation, the total amount of relative movement is small (approximately 0.5 millimeters), exhibiting a strictly periodic functional dependency on the rotation cycle of the wheel. Unfortunately, portions of this gross periodic movement are achieved through intermittent, microscopic stick-slip events (8-20 .mu.m incremental displacements), in turn, producing vibrations in the wheel cover. The wheel cover is suitably coupled to the air in a manner such that the cover vibrations produce fluctuations of sound pressure, subsequently propagating through the air medium, making the events audible to the occupants and nearby observers.
Several attempts have been made to reduce or eliminate noise such as squeaks. One attempt is to use elastomeric rings or adhesive tapes applied at an interface of the wheel cover and the wheel. Another attempt is to use tapes that are individually applied manually (as many as ten to twelve segments) at the interface of the wheel cover and the wheel. However, all of these attempts lack durability because the wheel eventually wears through the rings and tapes.
Therefore, it is desirable to provide a wheel cover with a durable, noise inhibiting feature. It is also desirable to provide a wheel cover for a wheel that eliminates squeaks and other noises. Therefore, there is a need in the art to provide a noise inhibiting wheel cover for a wheel of a vehicle.